Many non-actors, (and about half of the actors out there) have certain notions as to what makes a brilliant performance. If an actor can accomplish a certain achievement, people believe that by default, they are witnessing a genius at work.
One action which holds this misguided esteem in people is bringing forth real tears during a performance.
This skill is overrated in my view. While it may certainly be part of a great actor's arsenal, the ability to cry on cue is not by itself an indicator of greatness. It is not, in my estimation, even an indicator that any acting is taking place. Those that can cry on cue, (as fascinating as the talent may be in its own right) are doing little more than those who can whistle.
I mention this because I think that actual crying, with tears and such, is a goal a lot of actors work too hard at achieving. By actual crying, I mean the shedding of tears.
Yet acting is about being sincere in presentation of the character's emotions. Unless you just happen to have the gift of instant water works coupled with a keen understanding of what leads up to a character crying, the mere process of calling forth actual tears is usually noticeable from about 30 miles away.
People tend to forget that the act of crying only culminates in the production of tears. But tear production can take place for so many reasons other than weeping. Furthermore, a person may experience something that is, for all intents and purposes, weeping, with minimal tear production.
Physically, crying begins within the chest or throat, passes slowly from the back of the neck up to and encompassing the face. To skip these steps and try to start crying right out of your eyeballs is one of the worst, (and detectable) examples of fraud in the acting world. I have worked with actors guilty of this.
Setting aside the physical sensations, let us not forget the stimulus to the heart that takes place to bring about the weeping. Unless you are an infant, crying is rarely an instant action. The pain, the fear, the realization of the circumstances that bring about the tears all must be registered by the actor. If little has led up to it, you could summon forth Niagara Falls from your tear ducts at the drop of a hat, but it will not do you or the scene an ounce of good.
An actor who is committed to all aspects of a portrayal of weeping will give an audience an authentic and memorable performance, even if no visible tears show up.
Of course if they do show up along with a sincere performance, great. But if you find yourself laboring too much over producing tears, set it aside. Otherwise your performance may illicit the wrong type of tears from the audience.